290 PHYSIOLOGICAL KEGULATIONS 



has occurred. Of these correlatives all appeared to be equally 

 significant, for no means was found of distinguishing direct ties or 

 nexuses from others. All quantitative relations therefore equally 

 characterized the water relations of an organism or its parts, and 

 whatever was neglected through convenience or ignorance left the 

 description of the physiological relations incomplete by that much. 

 Possibly all of the changes are resistances to further increment and 

 promoters of recovery. 



A considerable number of modifications in composition and 

 metabolism were actually and quantitatively correlated with water 

 increment (± AW) ; extensive data were for the dog, represented in 

 figure 131. In that correlation, ± AW has the arbitrary status of 

 an independent variable ; but the relations are reciprocal among all 

 the quantities present. 



Finally, the role of forces in water exchanges, of bodily dimen- 

 sions, of developmental ages, and of other factors of heredity and 

 environment were considered. Each category emphasized par- 

 ticular aspects of the adjustments of water content. 



§ 106. Ufifokmities 



The qualitative results arising from the investigation outlined 

 are indicated by the specific conclusions now set forth. Each is an 

 induction from data already presented ; whenever exceptions to the 

 statements made shall turn up, they will be noteworthy and useful. 



(1) The living units studied respond to each change of water 

 content by (among other things) modifying their rates of water 

 exchange. 



(2) The modified exchange is of such a sign that excesses are 

 eliminated and deficits are paid off, when conditions allow. 



(3) Upper and lower limits of water content exist, compatible 

 with continued life and observed activity; outside these tolerated 

 loads, recovery of water balance usually does not occur. 



(4) The variability of water content of one individual in stand- 

 ard conditions is related to the amount of modification of exchange 

 rates that occurs per unit increment of water content (fig. 47). 



(5) Among differentiated channels or paths of water exchange 

 in any species, gain by only one path and loss by only one path is 

 markedly modified with water load (table 10). 



(6) In no case is water found to be manufactured from other 

 chemical substances at faster rates in response to water deficits. 



